Subterranean treatment fluids comprising polyoxazoline compositions and methods of use in subterranean formations

Abstract

The present invention relates to subterranean treatment fluids. In particular, the present invention relates to subterranean treatment fluid compositions that comprise polyoxazoline compositions and methods for using such compositions in subterranean applications. In one embodiment, the present invention provides a method of controlling shale swelling in a subterranean formation comprising introducing a treatment fluid into the subterranean formation, wherein the treatment fluid comprises a base fluid and a polyoxazoline composition. In another embodiment, the present invention provides a method of treating a portion of a subterranean formation comprising the steps of: introducing a treatment fluid that comprises a base fluid and a polyoxazoline composition; and treating a portion of the subterranean formation. Other embodiments are provided.

1. A method of controlling shale swelling in a subterranean formation comprising introducing a treatment fluid into the subterranean formation, wherein the treatment fluid comprises a base fluid and a polyoxazoline composition. 
     
     
       2. The method of  claim 1  wherein introducing the treatment fluid into the subterranean information involves drilling at least a portion of a well bore in the subterranean formation. 
     
     
       3. The method of  claim 1  wherein introducing the treatment fluid into the subterranean formation involves stimulating at least a portion of the subterranean formation. 
     
     
       4. The method of  claim 1  wherein introducing the treatment fluid into the subterranean formation involves a completion operation. 
     
     
       5. The method of  claim 1  wherein the treatment fluid is a drilling fluid. 
     
     
       6. The method of  claim 1  wherein the treatment fluid has a density of about 4 lb/gallon to about 22 lb/gallon when measured at sea level. 
     
     
       7. The method of  claim 1  wherein the base fluid is an aqueous-based fluid, or a nonaqueous-based fluid, or a mixture thereof. 
     
     
       8. The method of  claim 1  wherein the base fluid is selected from the group consisting of fresh water, saltwater, a brine, and seawater. 
     
     
       9. The method of  claim 1  wherein the base fluid comprises an organic fluid. 
     
     
       10. The method of  claim 1  wherein the base fluid is selected from the group consisting of a mineral oil, a synthetic oil, an ester, and a combination thereof. 
     
     
       11. The method of  claim 1  wherein the base fluid is present in the treatment fluid in an amount sufficient to make the treatment fluid pumpable into the subterranean formation. 
     
     
       12. The method of  claim 1  wherein the base fluid is present in the treatment fluid in an amount of from about 20% to about 99.99% by the volume of the treatment fluid. 
     
     
       13. The method of  claim 1  wherein the polyoxazoline composition is selected from the group consisting of a polyoxazoline; a polyoxazoline derivative; a chemically altered polyoxazoline; a polyoxazoline copolymer; and a combination thereof. 
     
     
       14. The method of  claim 1  wherein the polyoxazoline composition is selected from the group consisting of a polyoxazoline, a polyoxazoline derivative, a chemically altered polyoxazoline, and a polyoxazoline copolymer that has a molecular weight of between 2,000 and 50,000. 
     
     
       15. The method of  claim 1  wherein the polyoxazoline composition is selected from the group consisting of a polyoxazoline, a polyoxazoline derivative, a chemically altered polyoxazoline, and a polyoxazoline copolymer that has a molecular weight of between 100,000 and 700,000. 
     
     
       16. The method of  claim 1  wherein the treatment fluid further comprises one of the following: a weighting agent; a salt; a shale-inhibiting component; a viscosifier; a filtration control agent; a pH control agent; an emulsifier; or a combination thereof. 
     
     
       17. The method of  claim 1  wherein the subterranean formation comprises a thief zone. 
     
     
       18. A method comprising the steps of:
 introducing a treatment fluid that comprises a base fluid and a polyoxazoline composition into a portion of a subterranean formation comprising reactive shales; and 
 allowing the polyoxazoline composition to at least partially control shale swelling. 
 
     
     
       19. The method of  claim 18  wherein introducing the treatment fluid into the subterranean information involves drilling at least a portion of a well bore in the subterranean formation. 
     
     
       20. The method of  claim 18  wherein introducing the treatment fluid into the subterranean information involves stimulating at least a portion of the subterranean formation. 
     
     
       21. The method of  claim 18  wherein the treatment fluid is a drilling fluid. 
     
     
       22. The method of  claim 18  wherein the treatment fluid has a density of about 4 lb/gallon to about 221b/gallon when measured at sea level. 
     
     
       23. The method of  claim 18  wherein the base fluid is an aqueous-based fluid, or a nonaqueous-based fluid, or a mixture thereof. 
     
     
       24. The method of  claim 18  wherein the base fluid is present in the treatment fluid in an amount of from about 20% to about 99.99% by the volume of the treatment fluid. 
     
     
       25. The method of  claim 18  wherein the polyoxazoline composition is selected from the group consisting of a polyoxazoline; a polyoxazoline derivative; a chemically altered polyoxazoline; a polyoxazoline copolymer; and a combination thereof. 
     
     
       26. The method of  claim 18  wherein the treatment fluid further comprises one of the following: a weighting agent; a salt; a shale-inhibiting component; a viscosifier; a filtration control agent; a pH control agent; an emulsifier; or a combination thereof. 
     
     
       27. A method of drilling comprising the steps of:
 providing a drilling fluid that comprises a base fluid and a polyoxazoline composition; 
 drilling at least a portion of a well bore in a subterranean formation comprising reactive shales; and 
 allowing the polyoxazoline composition to at least partially control shale swelling. 
 
     
     
       28. The method of  claim 27  wherein the well bore is a water well or a hydrocarbon well. 
     
     
       29. The method of  claim 27  wherein the well bore is located offshore. 
     
     
       30. The method of  claim 27  wherein the drilling fluid has a density of about 4 lb/gallon to about 22 lb/gallon when measured at sea level. 
     
     
       31. The method of  claim 27  wherein the base fluid is an aqueous-based fluid, or a nonaqueous-based fluid, or a mixture thereof. 
     
     
       32. The method of  claim 27  wherein the base fluid is present in the drilling fluid in an amount of from about 20% to about 99.99% by the volume of the treatment fluid. 
     
     
       33. The method of  claim 27  wherein the polyoxazoline composition is selected from the group consisting of a polyoxazoline; a polyoxazoline derivative; a chemically altered polyoxazoline; a polyoxazoline copolymer; and a combination thereof. 
     
     
       34. The method of  claim 27  wherein the drilling fluid further comprises one of the following: a weighting agent; a salt; a shale-inhibiting component; a viscosifier; a filtration control agent; a pH control agent; an emulsifier; or a combination thereof.